The slewing device is composed of a brake valve, a slewing motor and a slewing gearbox. Through the slewing device and slewing bearing, the upper turntable of the excavator bites to rotate in all directions relative to the lower car body.
Rotary motor
Rotary motor is a swash plate axial piston motor, its structure is shown in Figure 5-6. The main parts of the motor are fixed swash plate 5, cylinder 9, plunger 8, valve plate 3, motor housing 6 and parking brake. The parking brake is a wet multi-plate brake, consisting of a center plate 1 and a friction plate 2. The swill shoes 4 are embedded in each plunger 8, and there are nine plungers with sliding shoes in the cylinder 9. The cylinder 9 is splined to the shaft 7.
The rotation speed of the rotary motor depends on the amount of oil delivered from the pump. The oil from the oil pump flows into the oil (A) from the motor to move the plunger from the bottom dead center to the top dead center. Then, the sliding shoe 4 slides along the fixed swash plate 5 to make the plunger 8 reciprocate linearly move in the cylinder 9.
When high-pressure oil enters the motor from the oil inlet, the rotation torque of the output shaft of the rotary motor is transmitted to the rotary reduction gearbox through the shaft 7 and the upper turntable is rotated. Return oil flows from the motor outlet and then returns to the hydraulic tank. When the high-pressure oil enters the co-rotating motor in the opposite direction to the above, the motor rotates in the opposite direction, and the upper turntable also reverses.
